Stepback mechanism for phonograph transcribers



Nov. 22, 1949 Filed April 21, 1944 T H. NAKKEN STEPBACK MECHANISM FOR PHONOGRAPH TRANSURIBERS 3 Shets-Sheet 1 IMHIIIIIHHHHH Q Nov, 322, 1949 T. H. NAKKEN 2,439,045

STEPBACK MECHANISM FOR iHONOGRAPH TRANSCRIBERS Filed April 21, 1944 3 Sheets-Sheet 2 T1 CF21.

.fa a 79 77 1 L 12 I F 5.5 27 --z0 J P22 TURNTABLE MOTOR AMPLIFIER INVENTOR. TheodoreMJl kk'cn BY Nov 22 1949 1": H. NAKKEN 2,439,045

STEPBACK MECHANISM FOR PHONOGRAPH TRANSCRIBERS Filed April 21, 1944 3 Sheets-Sheet 5 INVENTOR. Theod'o re H: flizk'iiew 105 1 02 I BY Patented Nov. 22, 1949 STEPBACK MECHANISM FOR PHONOGRAPH TRANSCRIBEBS Theodore H. Nakken, New York, ,N. Y., assignor to The Soundscriber Corporation, New Haven, Conn., a corporation of Connecticut Application April 21, 1944, Serial No. 532,163

13 Claims. 1

This invention relates to sound reproduction, and more particularly to improvements in a stepback mechanism for a phonographic transcriber. The present invention is especially designed for use on a dictating machine of the type disclosed in Patent No. 2,250,242, issued July 22, 1941, to Lincoln Thompson for Disk dictating machine. It constitutes an improvement on the stepback mechanisms disclosed in the prior Patents No.

2,240,321 of April 29, 1941, for Transcribing ma- Vide a stepback mechanism in which the pickup arm may be selectively advanced or back spaced for replaying any desired portion of the record.

A further object is to provide a stepback mechanism for a phonographic transcriber in which the movement of the pickup arm is accomplished in I two steps by the differential action of a pair of spring hinges of different strengths.

A further object of the invention is to provide an improved form of stepback mechanism of the above nature which will be relatively inexpensive to manufacture simple in construction, orna-' mental in appearance, easy to adjust and assemble, having the minimum of friction, and very efficient and durable in use.

With these and other objects in view, which will appear as the description proceeds, there have been illustrated on the accompanying draw- 'ings'two forms in which the invention may conveniently be embodied in practice.

In the drawings,

Fig. 1 is a perspective view of a transcribing machine embodying one form of the present invention.

Fig. 2 is a side view of the same.

Fig. 3 is a diagram showing the electrical circuits of the machine.

Fig. 4 is a sectional'view of the electromagnetic stepback mechanism, showing the construction of the slow-moving heavy bracket member and the rapid-moving light armature clapper.

Fig. 5 is a perspective view of the stiff hinge spring employed for connecting the bracket member of the stepback mechanism to the magnetic core frame.

Fig. 6 is a perspective view of the weak ushaped spring for attaching the armature clapper to the bracket member.

Fig. '7 is a sectional view taken along the line 'l'! of Fig. 4, looking in the direction of the arrows.

ing 22 at the bottom thereof.

Fig. 8 represents a left-hand end view of the bracket member.

Fig. 8a is a bottom view of the same.

Fig. 8b .is a right-hand end view of the same.

Fig. 9 is a perspective view of the movable angular armature clapper, showing the knife edge on the end thereof.

Fig. .10 is a perspective view of the stepback plate shown detached from the reproducer arm.

Fig. his a perspective view of a modified form of the invention employing an additional stepback mechanismlocated within a sector-shaped aperture of the stepback plate for permitting the reproducer arm to be advanced forwardly, as well as back-spaced.

Referring now to the drawings wherein like reference numerals designate like parts throughout 'disk supporting shell 14 having a square pin l5 atits upper end for centralizing the disk record ,andpreventing relative rotation between it and said shell.

The numeral lfiindicates a reproducer or playback arm which is mounted on a U-shaped bearing bracket having a cone pivot bearing 2| at the upper end thereof, and a ball and pin bear- The reproducer arm !5 is provided on its free end with a pickup head i! connected to said arm by means of a laterally playless" spring hinge l8,.and the end of the pickup head I! has a lifting handle IQ for convenience in manipulation.

In, order to permit stepback of the reproducing needle, whenever it is desired to replay a portion of the record, provision is made of a side plate 23 having a circular cam edge section 24 and a circular apertureZE located in a narrow extensionjit, attherear ofsaid plate 23 (see Fig.10).

The aperture 25 is adapted to fit over a shaft ,2! uponwhich the reproducing arm pivotsthus ,inFig. 3, A. 0. power is supplied to the apparatus through a socket ,3! to which a two-pronged plug 32 is adapted to be detachably connected. The plug 32 is connected by conductor 33, 34

to an amplifier 35, the conductor 33 having a main control switch 35a located therein for turnon and on the motor and amplifier. The anipliiier 35 is connected by means of conductors 3%, 3? to the pickup head I1, and the output of said amplifier 35 is connected by means of a pair of conductors 38, 39 to a sound reproducer such a headset 139, which is adapted to be worn by the transcribing operator.

Leading from the conductors 33, 34 are two succcssive pairs of conductors 4|, 42, and 43, 44 which transmit A. 0. power to the turntable motor it, previously mentioned. A pair of conductors 45, 46 also lead from the power line conductors 33, 34 to a rectifier 41, the output of which is connected by a pair of conductors 48, 49 to an electromagnet coil 59the conductor 49 having a foot switch located therein, permitting the transcribing operator to manually control the operation of the turntable brake. The coil 5!] surrounds an iron core 52 which is adapted to energize a light weight iron brake-operating armature 53 which is normally pulled to the left, as

viewed in Figure 3, by a spring 54. At the end of the armature 53, provision is made of a brake shoe 55 for engaging a depending flange 55 of the shell III which surrounds the turntable II.

A pair of conductors 51, 58 serve to connect the rectifier 41 to an electromagnetic coil 59 of the stepback mechanism, said coil 59 having a pair of terminal lugs 60, 6| joined to the conductors 51, 58 respectively.

Within the inside of the coil 59 provision is made of a cylindrical iron core 62 which is secured by a machine screw 53 to the base of an angular magnetic frame 64 having an arm 65 which is provided with a side extension 65a hava pair of apertures 65, 61 for receiving screws 61a, 51b for attaching the frame 64 to the cabinet II]. The arm 55 of the angular frame 64 is adapted to be connected at its upper end to a stiff rectangular leaf spring hinge 68 by means of pair of screws 69, as clearly shown in Fig. 4.

Provision is also made of a relatively thick nonmagnetic rectangular bracket 19 secured to the stiff spring 68 by means of a pair of connecting screws II. The bracket is provided with a grooved base 12 and a pair of opposed end extensions 12a, 121), as clearly shown in Fig. 8. The sides of the base 12 are provided with tapped apertures Ha, Ha, which receive the screws TI, and are adapted to embrace a lightweight angular iron armature (or clapper) 13 having a lateral arm 14 provided with a knife edge 15, which is in alignment with the curved end edge 24 of the plate 23, previously mentioned.

The armature 14 is attached as by a pair of screws 15, to a relatively weak non-magnetic U-shaped leaf spring hinge 11, which serves to resiliently connect said armature 14 to said bracket Ill. The base of the U-shaped spring has a pair of screw holes 18, 19 and another pair of screw holes 80, 8| are located in the legs of said spring 11, the latter being adapted to receive screws 32, for connecting the U-shaped hinge to the bracket 10.

The numeral 84 indicates an aperture formed in the intermediate portion of the armature 13, which aperture is adapted to loosely surround a stop screw 85 which is screwed into a tapped hole 95 in the central portion of the bracket 10. Provision is also made of a stop screw 81, which is screwed into one leg of an angle member 88,

the other leg of which is attached by means of screws 88a to the magnetic frame 66 (see Fig. 4).

A lock nut 89 is provided on the screw SI for holding it in adjusted position. Provision is also made of a pair of spacing lock washers 9t and 9! for holding the weak spring hinge 11 offset from the armature 14.

In order to control the operation of the stepback mechanism, provision is made of a foot switch 92 mounted upon a base board 93, upon which the brake-controlling foot switch BI is also mounted, it being understood that the switch 92 will normally be held in open position by means of a spring located within said switch, and the switch M will also be held open by such a spring.

Operation In operation, when the coil 59 is energized by actuation of the foot switch 92, the rear of the iron armature 13 will be attracted by the core 62 and said armature will move rapidly around the pivot axis of the weak spring hinge ll until the knife edge 15 engages and is stopped by the edge 24 of the stepback plate 23.

The armature 13 which up to this time has been acting independently, will thereafter move in combination with the relatively heavy bracket 19 to which it is secured. The motion of the knife edge 15 during this latter period will take place slowly around an axis in the stiff spring GB, and thus accomplish the necessary stepback in two successive steps, due to the differential action of the spring hinges (58 and 11.

When the magnet is deenergized by releasing the pedal of the foot switch 92, the knife edge '55 will be first unclutched and will swing back away from the stepback plate 23 under the action of the spring 11-the whole assembly will then swing back to its original position under the action of the spring 68.

It will be understood that the stop screw will limit the inward motion of the armature l4 and the associated bracket 10, while the stop screw 81 will limit the outward motion of said parts.

Modified form In the modified form of the invention, shown in Fig. 11, provision is made of a sector-shaped stepback plate 94 which is provided with an aperture 95 surrounding an inside stepback mechanism I99 similar to that previously described. The outer end of the plate 94 is provided with two concentric arcuate edges 96, 91 for permitting engagement by the knife edges 98, 99 of the inside stepback mechanism I09, and an outside advance mechanism I9I, respectively. The stepback mechanism Hi0, and the advance mechanism IOI are adapted to be selectively operated independently by a pair of foot switches I92, I03, respectively, as clearly shown in Fig. 11, said switches being mounted upon a pair of base boards I94, I95.

While there have been disclosed in this specification two forms in which the invention may be embodied, it is to be understood that these forms are shown for the purpose of illustration only, and that the invention is not to be limited to the specific disclosures, but may be modified and embodied in various other forms without cleparting from its spirit. In short, the invention includes all the modifications and embodiments coming within the scope of the following claims.

Having thus fully described the invention, what is-claimed asnew, and for which it is desired to secure Letters Patent, is:

1. In a phonographic transcriber of the type having a reproducing arm carrying a pickup needle which is mounted to swing across a rotating disk record, a pivot shaft for said arm, said arm having a side extension provided with an aperture fitted over said shaft, said side extension having a circular cam edge concentric with said shaft to insure that said edge will always be exactly at thesame distance from the axis of said shaft,-and means to'engage said camand movable in a direction tangent to said cam edge to swing said arm a short distance over said record.

2. The invention as defined in claim 1 in which said side extension has a vertical flange for attachment to the side of said reproducer arm.

3. In a phonograph transcriber, a reproducer arm carrying a pickup head pivotally mounted to move over the surface of a rotating disk record to be transcribed, a cam connected to said arm, and electromagnetically-operated means to engage said cam and move said arm rearwardly to step back said head a predetermined number of grooves, said means including an electromagnetic coil, an iron core energized thereby, a light armature in the field of said coil having a knife edge for engaging said cam, and differential spring means for flexibly connecting said armature to said core to permit said knife edge to first clutch said cam rapidly and thereafter cause it to move rearwardly slowly.

4. In a phonograph transcriber, a reproducer arm carrying a pickup head pivotally mounted to move over the surface of a rotating disk record to be transcribed, a cam connected to said arm, and electromagnetically-operated means to engage said cam and move said arm forwardly to advance said head a predetermined number of grooves, said means including an electromagnetic coil, an iron core energized thereby, a light armature in the field of said coil having a knife edge for engaging said cam, and differential spring means for flexibly connecting said armature to said core to permit said knife edge to first clutch said cam rapidly and thereafter cause it to move forwardly slowly.

5. In a phonographic transcriber of the type having a reproducing arm carrying a pickup needle which is pivotally mounted to swing across a rotating disk record, said arm having a side extension provided with a pair of cam edges concentric with the pivotal axis of said arm, and separate manually-controlled means movable tangent to said cam edges to clutch said cam edges selectively to step back and advance said arm a predetermined number of grooves respectively.

6. In a phonographic transcriber of the type having a reproducing arm carrying a pickup needle which is pivotally mounted to swing across a rotating disk record, said arm having a side extension provided with a pair of cam edges concentric with the pivotal axis of said arm, and separate manually-controlled electromagnetically energized means movable tangent to said cam edges to clutch said cam edges selectively to step back and advance said arm a predetermined number of grooves respectively.

7. In a phonographic transcriber of the type having a reproducing arm carrying a pickup needle which is pivotally mounted to swing across a rotating disk record, said arm having a side extension provided with a pair of cam edges concentric with the pivotal axis of said arm, and separate manually controlled means to clutch tax said cam edgesseiectively'to step back and. advance said arm a predetermined number of grooves respectively, said side extension having an interior sector-shaped aperture forming a circular are on the periphery of said extension with one of said camedges located on the inside of said are and the other cam edge located on the exterior of said arc, one of said manually-controlled'means being located within said aperture for engaging said interior cam edge and the other manually-controlled means located outside said side: extension for engaging said exterior cam edge.

8. In a phonographic transcriber of the type having a reproducing arm carrying a pickup needle which is pivotally mounted to swing across a rotating disk record, said arm having a side extension provided with a pair of cam edges concentric with the axis of said arm, separate manually controlled electromagnetically operated means to clutch said cam edges selectively to step back and advance said arm a predetermined number of grooves, and a pair of foot switches for operating said separate clutch means respectively.

9. In a phonographic transcriber of the type having a reproducing arm carrying a pickup needle which is mounted to swing across a rotating disk record, said arm having a side extension provided with an arcuate cam edge concentric with the pivotal axis of said arm, an electromagnetic coil, a core located within said coil, an angular frame secured to one end of said core, a bracket pivotally secured to said frame by a stiff spring, an angular iron armature clapper pivotally secured to said bracket by a weak spring, said armature having a knife edge to clutch said arcuate cam edge, the differential action of said springs permitting said armature to 1 first engage and clutch said cam edge rapidly.

and then to move slowly with said bracket to step back said arm in response to the attraction of said core.

10. In a phonographic transcriber of the type having a reproducing arm carrying a pickup needle which is mounted to swing across a rotating disk record, said arm having a side extension provided with an arcuate cam edge concentric with the pivotal axis of said arm, an electromagnetic coil, a core located within said coil, an angular frame secured to one end of said core, a bracket pivotally secured to said frame by a still spring, an angular iron armature clapper of light weight pivotally secured to said bracket by a weak spring, said armature having a knife edge to clutch said arcuate cam edge, the differential action of said springs permitting said armature to first engage and clutch said cam edge rapidly and then move slowly with said bracket to step back said arm in response to the attraction of said core.

11. In a phonographic transcriber of the type having a reproducing arm carrying a pickup needle which is mounted to swing across a rotating disk record, said arm having a side extension provided with an arcuate cam edge concentric with the pivotal axis of said arm, an electromagnetic coil, a core located within said coil, an angu lar frame secured to one end of said core, a bracket pivotally secured to said frame by a stiff spring, an angular iron armature clapper pivotally secured to said bracket by a weak U-shaped spring, said armature having a knife edge to clutch said arcuate cam edge, the differential action of said springs permitting said armature to 7 first engage and clutch said cam edge rapidly, and then to move slowly with said bracket to step back said arm in response to the attraction of said core.

12. The invention defined in claim 9 in which 5 to limit the movement of said armature clapper when attracted by said electromagnetic core.

THEODORE H. NAKKEN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 10 Number Name Date 1,438,000 Underhill Dec. 5, 1922 2,079,515 Ligh May 4, 1937 

